In machines for producing a web of paper or paper board, it is common to direct an endless rope or a pair of endless ropes around the end portions of a series of rolls, such as the rolls of the dryer section or a set of calendar rolls, for gripping and threading through the rolls the leading end portion of a web, usually referred to as a "tail". When a single rope is used, it is directed twice around the rolls so that two adjacent ropes extend through the rolls and are effective to pinch the tail and thread it around the rolls. The rope may have a diameter of about one half inch and is usually made of spun nylon filaments or of natural fibers. The rope stretches over a period of use, especially when the rope is driven at a higher speed, for example, over several thousand feet per minute. The ropes can stretch from 7% to 10% within a few days or within a few months depending upon the speed of the papermaking machinery. In the dryer section, the length of the endless rope is frequently between 200 feet and 400 feet so that a 7% to 10% stretch requires substantial take up in the rope in order to maintain the desired rope tension.
In prior art rope stretchers, various types of elongated frames have been fabricated from metal rods and bars of various shapes, and the fabricated steel frames support movable carriages. Flexible cables extend from the carriages around corresponding stationary guide pulleys and also around movable pulleys supported by the extendable piston rods of fluid cylinders. In such a rope stretcher, it is desirable to simplify its construction and to reduce the number of moving parts so that servicing is minimized or substantially eliminated thereby avoiding down time of the papermaking machine in the event the rope stretcher is not properly serviced. It is also desirable to maintain constant tension in the rope to provide dependable and efficient threading of a web tail and to obtain maximum service life from the rope. In addition, it is highly desirable to provide a more compact rope stretcher having a lighter weight and greater strength as well as a rope stretcher which may be installed in any position on papermaking machinery.